By John Kwoba

NAIROBI, Oct. 13 (Xinhua) -- Kenyan Olympic silver medalist Sally Kipyego has failed to regain fitness after she took long to recover from a bout of malaria and will miss the New York marathon on Nov. 4.

Kipyego, who now runs for the USA, won silver for Kenya at the London Olympics in 2012 in the 10,000m distance.

The 2016 New York marathon silver medalist (2:28:01) had skipped the 2017 season to give birth to her first baby and was hopeful of returning to top action.

However, that plan will have to wait until she recovers her strength after the malaria bout.

"I'm devastated to announce that I will not be running the New York marathon. I had a bad case of malaria and pneumonia in the middle of my build-up that took me longer than expected to recover," said Kipyego on Saturday.

"As much as I feel disappointed, my training will always be a great reminder of the good work I have done for months. Until next time, the work continues," he added.

Kipyego was expected to challenge for medals against Shalane Flanagan, the 2017 winner, and 2018 Boston Marathon champion Des Linden as well as Kenya's Mary Keitany, who was second last year and London marathon champion Vivian Cheruiyot.

With Kipyego out of the equation, Keitany will be targeting a fourth victory on return to New York City.

Keitany and her compatriot 5,000m Olympic Games champion Vivian Cheruiyot will join Flanagan and Linden of the US in a race that features 10 Olympians.

Keitany, 36, is the women's only marathon record-holder who finished runner-up in this race last year after notching three successive titles.

In 2016, she had a dominating performance in which she surged ahead at Mile 14 to finish the course on a solo run in 2:24:26.

Her 3:34 margin of victory was the greatest in the women's race since 1980, and she became the first able-bodied runner since Grete Waitz to win the event three years in a row.

"I was disappointed not to defend my title last year, but I was not 100 percent healthy and Shalane ran a strong race," said Keitany, the 2012 and 2016 World Marathon Majors champion.

In April 2017, Keitany won her third London Marathon title, breaking the women's only marathon record in a blistering time of 2:17:01.

Joining Keitany will be two Ethiopians, reigning World Half Marathon champion Netsanet Gudeta and Mamitu Daska, who finished third in New York last year.